Interpretive Summary: Crape myrtle is an economically important ornamental species. For breeding enhanced varieties and varietal identification it is imperative to have DNA markers that help in these pursuits. This work is on the isolation and characterization of DNA markers for crape myrtle. The DNA markers where then validated on 33 cultivars and accessions to determine allele frequency (differences) for each DNA marker. The results indicated a relatively high genetic diversity in the material tested, which is good for developing new cultivars. Testing of these DNA markers on related species indicates they are portable.

Technical Abstract:
Lagerstroemia L. (crape myrtle) is an economically important woody plant genus with several deciduous flowering ornamental species. A wide range of flower colors, long flowering periods, growth habits ranging from miniature to tree sizes, and exfoliating bark characteristics provide horticulturists and nursery growers with a great deal of interest in the breeding and genetics of this genus. We report microsatellite marker development from a GT-enriched genomic library of the interspecific hybrid ‘Natchez’ (L. indica L. x L. fauriei Koehne). Twelve of 43 novel microsatellite loci were characterized on a collection of 33 Lagerstroemia cultivars and accessions. Four to eight alleles per locus (mean = 5.6 alleles) were detected. Allelic richness ranged from 3.9 to 7.2 with a mean of 5.3. The level of polymorphism detected (average gene diversity of 0.68) indicates moderately high genetic diversity within the selections of crape myrtle cultivars and accessions. The examined markers also exhibited high cross-species transferability to L. fauriei, L. limii Merr., and L. subcostata Koehne.